The present invention relates to a metallic seal for the containment of high pressure fluids, including gases, from cryogenic to highly elevated temperatures. More particularly, the present invention relates to pressure-energized, annular metallic lip seals with lateral offset, angular and axial misalignment capability.
In the field of fluid containment of high pressure fluids, resilient metallic seals are employed in applications where elastomeric and polymeric materials cannot be used because of extremely high pressures, high temperatures and/or aggressive media. Such sealing devices are produced in different configurations designed to meet a variety of operating requirements.
One such seal is the “Axial C-Seal”, show in FIGS. 1A and 1B, which was developed as an improvement in flexibility over the hollow metal o-ring. Like the metal o-ring, the axial c-seal may be used to seal gaps between cylindrical surfaces, in mainly static application.
Other seals have been developed to perform this function, for example, those shown in the following U.S. Pat. Nos.: 4,457,523; 4,854,600; 5,799,954; 6,257,594; and 6,446,978. All of these seals serve their purpose, but have limitations when required to be both pressure-energized and capable of accommodating significant misalignments of the cylindrical surfaces to be sealed.
In devices known as couplings, a rigid hollow proboscis or probe is inserted into a hollow receptacle in a fluid transmission system. The receptacle contains a sealing ring or multiple sealing rings, which are dilated by the inserted probe, thereby creating the required contact stresses to achieve fluid containment between the two bodies to be sealed together.
C-seals are presently employed in couplings. Occasionally, due to imperfect field installation practices, the probe will be forced into the receptacle before the centerlines or axes of the two components are properly aligned. When this occurs, the probe may dent one side of the c-seal, which may not be sufficiently resilient to elastically deform, and therefore may leave a gap on the opposite side which results in leakage of fluid when the joint is pressurized.
It is highly desirable to provide an improved metallic seal which overcomes the foregoing problems.